On Tue, Oct 02, 2012 at 03:32:55PM +0530, Sekhar Nori wrote: > On 10/1/2012 6:02 PM, Matt Porter wrote: > > On Mon, Oct 01, 2012 at 05:34:02PM +0530, Sekhar Nori wrote: > >> Hi Matt, > >> > >> On 9/29/2012 1:07 AM, Matt Porter wrote: > >>> L3RAM (shared SRAM) is needed for use by several drivers. > >>> This creates a genalloc pool and a hook for the platform code > >>> to provide the struct gen_pool * in platform data. > >>> > >>> Signed-off-by: Matt Porter <mporter@xxxxxx> > >> > >> I am not sure if any of the DaVinci devices have a need to allocate from > >> *both* ARM RAM and shared RAM. Shared RAM is not present on all DaVinci > >> devices AFAIR, and on DA850, there is just 8KB ARM RAM so I am not sure > >> if there is much point in trying to allocate from there. > >> > >> Can you instead see if Ben's earlier patch[1] to use shared RAM for SRAM > >> allocation on DA850 makes sense for your case? If yes, can you repost > >> with Ben's patch included in your series instead of this patch? I would > >> prefer that over creating a new pool for shared RAM. > > > > Hrm, I did look at Ben's earlier patch. The reason I added a separate > > pool mostly was so I didn't have to touch the PM code at all. That can > > continue using the private SRAM API with the ARM RAM as it is now. The > > But you dont have to touch the PM code. PM code can continue using SRAM > API. I have verified in the past that PM can work using shared RAM. > > > idea here was to allow that to be separate since no other bus masters > > can access the ARM RAM anyway and do something that didn't require > > regression testing PM. Also, I figured there's really no reason to use > > even a tiny bit of the shared SRAM on PM if we have that ARM RAM there > > and working fine for that use case. > > I see no reason why PM would break with shared RAM. I have not even seen > reports of shared RAM being short of size so we need to save space by > having PM code in ARM RAM. I can test the changes before the code is > committed and it will get tested in linux-next as well. Ok, sounds good to me. > > The other thing is that Ben's patch needs to be rewritten to at least > > have the hook I added so we can provide the gen_pool in platform data. > > If you prefer this path still, I can add the needed hook on top of his > > original patch. Ultimately, I only *need* genalloc support for the > > shared sram so I can remove the private SRAM API from uio_pruss...so I'm > > happy with any way to get at it. > > Right, I prefer just adding the hook so that genalloc can be used along > with SRAM API. Ok. > > Oh, and to be honest...it's not just for uio_pruss, but also to cleanly > > remove the private SRAM API usage from the davinci ASoC driver too. > > Audio can use the shared RAM too. And once all users of the SRAM API are > gone, only the hook to help pass the gen_pool as platform data needs to > remain. Right, I think we are on the same page now. I'll post an update to Ben's original patch with required gen_pool hook for pdata use. I noticed the beginning of DT support for davinci and the DT-based genalloc driver, https://patchwork.kernel.org/patch/1421961/, fits into that well. -Matt -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
